T. R. Malthus's An Essay on the Principle of Population, as It Affects the Future Improvement of Society rejected the idea that in animals some of the offspring will possess the desirable qualities of the parents in a greater degree.

1800

Erasmus Darwin's Zoonomia attempted to explain organic life according to evolutionary principles.

First volume of Charles Lyell's Principles of Geology interprets earth history as a process of gradual change.

1831

Darwin leaves England on H.M.S. Beagle, embarking on a five-year voyage of discovery.

1848

Asa Gray published Manual of the Botany of the Northern United States and founded systematic botany in the U.S. He later became Darwin's chief advocate in the U.S.

1858

Alfred R. Wallace proposed in a letter to C. Darwin a theory of evolution by means of natural selection based on his work in Indonesia. The two agreed to present their papers on the same occasion to the Linnean Society.

1859

Charles Darwin published On the Origin of Species; or, The Preservation of Favoured Races in the Struggle for Life.

1863

Thomas Henry Huxley's Man's Place in Nature stressed the similarities between humans and apes.

1863

Lyell's Antiquity of Man popularized the belief that the human race is much older than allowed by the biblical time scale.

1866

Ernst Haeckel's Generelle Morphologie advocated a radically materialist interpretation of progressive evolution.
Gregor Mendel published the results of his investigations of the inheritance of "factors" in pea plants.

1871

Charles Darwin published The Descent of Man and Selection in Relation to Sex.

1882

Darwin died and was buried in Westminster Abbey next to Sir Isaac Newton.

1893

August Weismann's The Germ Plasm stressed the role of "hard" heredity and precipitated a debate on Lamarckism.

1900

Correns, Tschermak and De Vries rediscovered Gregor Mendel's laws of heredity. Hugo De Vries went on to advocate evolution by sudden "mutations."

1902

W. Sutton pointed out the interrelationships between cytology and Mendelism, closing the gap between cell morphology and heredity.

J. B. S. Haldane's The Causes of Evolution suggested that altruistic acts toward close relatives might favor the survival and spread of those of the altruist's genes that are shared by relatives.

1937

T. Dobzhansky, an architect of the evolutionary synthesis, published Genetics and Origin of Species, which combined the best elements of both genetics and systematics.

1942

Ernst Mayr, another architect of the evolutionary synthesis, published Systematics and the Origin of Species .

1944

Julian Huxley's Evolution: The Modern Synthesis and George Gaylord Simpson's Tempo and Mode in Evolution consolidated the synthesis of Darwinism and genetics.

O. Avery, M. McCarty, and C. MacLeod determined that DNA was the substance that changed hereditary patterns in bacteria and must be the heredity material.

1951

Barbara McClintock published her hypothesis of transposable elements to explain color variations in corn.

1953

J. D. Watson and F. H. C. Crick published the structure for DNA in Nature.

1957

H.D. Kettlewell studied the peppered moth population in England and observed that light-colored moths survived best on trees with healthy lichens and dark-colored moths on lichens darkened by industrial pollution. The result was a difference in the allelic frequencies of dark and light moths in polluted and clean woods.

Jacob, Lwoff, and Monod shared the Nobel Prize for their discoveries concerning the genetics of prokaryotes and the Operon theory.

1968

J. D. Watson published The Double Helix , a history of the discovery of the structure of DNA.

F. J. Ayala in studies with Drosophila demonstrated that populations with variation adapted twice as fast as uniform populations.

1971

Kimura's Theoretical Aspects of Population Genetics placed him in the neutralist school along with Lewontin on interpretations of polymorphism.

1975

Edward O. Wilson's Sociobiology precipitated a controversy over the use of natural selection to explain human behavior.

1977

In Ontogeny and Phylogeny, Stephen J. Gould, a co-developer of the theory of punctuated equilibrium, says the fossil record does not support gradualism. The theory provides an explanation of the gaps existing in the fossil record.

1977

T. Dobzhansky's Evolution provides a longer, more technical but still conventional, up-to-date treatment of the synthetic theory.

1980

Fredrich Sanger produced the first complete sequence of a genome in a bacteriophage.